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New constraints on the cosmic mid-infrared background using TeV gamma-ray astronomy

Very high energy gamma-ray data obtained by CAT and HEGRA from active galactic nucleus Mkn 501 are used to constrain the cosmic Mid-Infrared background. While the entire infrared and submillimeter spectrum shape based on models has been fixed and the density scaled as a whole in previous studies, recent measures on the low and high energy infrared background are extensively used in this paper. In this original approach, the infrared distribution is only varied in the unexplored 3.5-100 microns region. With conservative hypothesis on the intrinsic spectra of Mkn 501, an upper limit of 4.7 nW.m-2.sr-1 between 5 and 15 microns is derived, which is very close to the lower limit inferred from deep ISOCAM cosmological surveys at 15 microns. This result is shown to be independent of the exact density of the lambda < 3.5 microns and lambda > 100 microns infrared distribution within the uncertainties of the measurements. Moreover, the study presented here rules out a complete extragalactic origin for the 60 microns excess found by Finkbeiner et al. (2000).